1. Field of the Invention
The present invention relates to a method for manufacturing a pixel structure, and more particularly to a method for manufacturing a pixel structure with use of a relatively fewer number of photomasks.
2. Description of Related Art
With the progress of modern visual information technology, various types of displays have been widely adopted in consumers' electronic products such as cell phones, notebook computers, digital cameras, and personal digital assistants (PDAs). Among these displays, liquid crystal displays (LCDs) and organic electroluminescence displays (OELDs) have become the mainstream on the market due to their advantages of lightness, compactness, and lower power-consumption. The manufacturing processes for both the LCDs and the OELDs include forming a pixel structure array over a substrate through a semiconductor manufacturing process.
FIGS. 1A through 1G are cross-sectional views depicting a process of manufacturing a conventional pixel structure. First, referring to FIG. 1A, a gate 20 is formed on a substrate 10. Next, referring to FIG. 1B, a first dielectric layer 30 is formed on the substrate 10 to cover the gate 20. Thereafter, referring to FIG. 1C, a channel layer 40 is formed on the first dielectric layer 30. Afterwards, referring to FIG. 1D, a source 50 and a drain 60 are formed on the channel layer 40. Referring to FIG. 1E, a second dielectric layer 70 is then formed over the substrate 10 to cover the channel layer 40, the source 50 and the drain 60. Next, referring to FIG. 1F, a contact hole H is constructed in the second dielectric layer 70. After that, referring to FIG. 1G, a pixel electrode 80 is formed on the second dielectric layer 70. The pixel electrode 80 is partly filled in the contact hole H and is electrically connected to the drain 60. Up to here, the fabrication of the pixel structure 90 is completed.
To sum up, the fabrication process of the pixel structure 90 is mainly carried out by forming the gate 20 with use of a first photomask, forming the channel layer 40 with use of a second photomask, forming the source 50 and the drain 60 with use of a third photomask, forming the contact hole H with use of a fourth photomask, and forming the pixel electrode 80 with use of a fifth photomask. Accordingly, the conventional five-photomask process of fabricating the pixel structure 90 is rather complicated and time-consuming, which leads to higher risk of defects and lower yield of the pixel structure 90. In addition, with the complicated manufacturing process and excessive time consumed for fabrication, the total manufacturing costs arisen from the fixed costs on the machines or the material costs are then increased.